Endovascular prostheses are sometimes used to treat aortic aneurysms. Such treatment includes implanting a stent or stent-graft within the diseased vessel to bypass the anomaly. An aneurysm is a sac formed by the dilation of the wall of the artery. Aneurysms may be congenital, but are usually caused by disease or, occasionally, by trauma. Aortic aneurysms which commonly form between the renal arteries and the iliac arteries are referred to as abdominal aortic aneurysms (“AAAs”). Other aneurysms occur in the aorta, such as thoracic aortic aneurysms (“TAAs”) and aortic uni-iliac (“AUI”) aneurysms. A TAA may occur downstream the aortic arch, i.e., in the descending aorta. Alternatively, a TAA may occur in the aortic arch itself, where the aorta branches to supply the brachiocephalic, left carotid and subclavian arteries, or may occur in the ascending aorta.
Endo-Vascular Aneurysm Repair (EVAR) has transformed the practice of treatment of aortic aneurysms from an open surgical approach to a much less invasive surgical approach. The first step of an endovascular intervention usually requires introducing a delivery system into the vasculature of a subject. If the crossing profile, i.e., the external diameter, of the delivery system is 24 Fr or lower (3 Fr=1 millimeter), a true percutaneous approach may be used, because vascular closure devices are available for proper closure of such puncture sites.
Blood vessels occasionally weaken or even rupture. For example, in the aortic artery, the vascular wall can weaken or tear, resulting in dangerous conditions such as aneurysm and dissection. Treatment of such conditions can be performed by implanting a prosthesis within the vascular system using minimally-invasive surgical procedures. An endoluminal prosthesis typically includes one or more stents affixed to graft material and is delivered to the treatment site by endovascular insertion. Once the endoluminal prosthesis is radially enlarged, it should remain in place indefinitely by self-attachment to the vessel wall, acting as a substitute vessel for the flow of blood or other fluids.
Aortic dissection is a tear or partial tear in the inner wall of the aorta, which causes blood to flow between the layers of the wall of the aorta, forcing the layers apart. Aortic dissections may be divided into two types in accordance with the Stanford classification: Type A dissections involve the ascending aorta and/or aortic arch, and possibly the descending aorta. Type B dissections involve the descending aorta or the arch (distal to right brachiocephalic artery origin), without involvement of the ascending aorta.
US Patent Application Publication 2007/0016281 to Melsheimer describes an introducer apparatus for deploying a self-expandable medical device, such as a stent, to a target area of a body vessel of a patient. The introducer apparatus comprises a shaft having a proximal end and a distal end, and a distal end portion disposed at the shaft distal end. The distal end portion comprises an introducer body and at least one deployment member. The introducer body is sized and shaped relative to the self-expandable medical device such that the medical device is receivable on a surface of the introducer body when the medical device is in a compressed condition. The deployment member is configured and arranged relative to the introducer body for selectively restraining the self-expandable medical device in the compressed condition on the introducer apparatus surface.
US Patent Application Publication 2013/0131783 to Shalev et al. describes medical apparatus for insertion into a mammalian body. The apparatus includes structural stent elements, at least a portion of which are shaped so as to define (a) at least one generally circumferential band, and (b) a plurality of engagement members that are joined to and extend radially inwardly from the band. The apparatus further includes an elongated latch member which is threaded through the engagement members, thereby physically latching the engagement members. The band and the engagement members are configured such that (a) when the latch member is threaded through and thus physically latches the engagement members, the engagement members retain the band in a radially-compressed state, and (b) when the latch member is removed from the engagement members, the band assumes a radially-expanded state. Other embodiments are also described.
US Patent Application Publication 2006/0190070 to Dieck et al. describes devices, systems and methods for stenting body lumens. In particular, stents are described which are advanceable directly over a guidewire and expandable within a target location of a body lumen by retraction of the guidewire and/or by releasing constraining element(s) disposed around at least a portion of the stent. Typically the constraining element(s) have the form of one or more bands or layers of material which hold the stent in an unexpanded configuration. These stent designs allow delivery to a body lumen without the need for a number of additional devices which are typically used in the delivery of conventional stents, thereby reducing the profile of the stent during delivery, increasing the flexibility of the stent during delivery to allow passage through more tortuous pathways, and allowing the delivery of branched or otherwise connected stents to body lumens, such as branched lumens.